Data transmission method, radio network controller and base station

ABSTRACT

The invention is related to a data transmission method in a telecommunication system. The method comprises determining the number of bit rate classes, setting bit rates for the bit rate classes, setting a maximum transmission power target, arranging resource requests into a queue, allocating resources according to the requests in the queue until the maximum power target is achieved.

FIELD

The invention relates to a data transmission method in atelecommunication system.

BACKGROUND

For the end user the most important thing in telecommunication networksis naturally that he can be satisfied with the end-to-end services heuses. In UMTS (Universal Mobile Telecommunication System) the quality ofservice is determined using a QoSt concept, in other words Quality ofService. An end-to-end service sets requirements regarding QoS. Therequirements are mapped to the following hierarchical level, which inturn performs QoS mapping for the following level and so on. To make themapping possible, the QoS requirements are classified.

For the end user, the impression of the connection quality typicallyrelates to the delay experience. This is the main reason why theconnection delay is the general separating characteristic between QoSclasses. Another important characteristic is, for instance, a guaranteedbit rate, which in practice typically means bandwidth.

The problem is that at the same time, when the end user is being offereda service of a satisfying quality, the limited radio resources have tobe used efficiently. To achieve this target, the bit rates have to beallocated economically: the bit rates have to be high enough to providethe required service but not unnecessarily high to avoid wasting ofresources.

BRIEF DESCRIPTION OF THE INVENTION

It is an object of the invention to provide an improved method toallocate bit rates especially for packet transmission. This is achievedby a data transmission method in a telecommunication system. The methodcomprises determining the number of bit rate classes, setting bit ratesfor the bit rate classes, setting a maximum transmission power target,arranging resource requests into a queue, allocating resources accordingto the requests in the queue until the maximum power target is achieved.

The invention also relates to a data transmission method in atelecommunication system, comprising determining the number of bit rateclasses, setting bit rates for the bit rate classes, setting a maximumtransmission power target, arranging resource requests into a queue,allocating resources according to the requests in the queue, if themaximum power target is not achieved when resources have been allocatedto all the users in the queue increasing the bit rates on the basis ofthe queue until the maximum power target is achieved, if the resourcerequests cause too much load in relation to the maximum power targetdecreasing the required number of bit rates in a predetermined way.

The invention also relates to a radio network control comprising meansfor determining the number of bit rate classes, means for setting bitrates for the bit rate classes, means for setting a maximum transmissionpower target, means for arranging resource requests into a queue, meansfor allocating resources according to the requests in the queue untilthe maximum power target is achieved.

The invention also relates to a radio network control comprising meansfor determining the number of bit rate classes, means for setting bitrates for the bit rate classes, means for setting a maximum transmissionpower target, means for arranging resource requests into a queue, meansfor allocating resources according to the requests in the queue, meansfor increasing the bit rates on the basis of the queue until the maximumpower target is achieved, means for decreasing the required number ofbit rates in a predetermined way.

The invention also relates to a base station comprising means forarranging resource requests into a queue, means for allocating resourcesaccording to the requests in the queue.

The invention also relates to a base station comprising means forarranging resource requests into a queue, means for resources accordingto the requests in the queue, means for increasing the bit rates on thebasis of the queue until the maximum target set for the transmissionpower is achieved, means for decreasing the required number of bit ratesin a predetermined way.

Preferred embodiments of the invention are described in the dependentclaims.

The method and system of the invention provide several advantages. Apreferred embodiment of the invention offers the operator a possibilityto control the separation of the Quality of Service classes. It is alsopossible to increase or decrease the bit rates and thus to adjust theload to the target set for the maximum transmission power. Therebylimited radio resources are used efficiently.

LIST OF THE DRAWINGS

In the following, the invention will be described in greater detail withreference to the preferred embodiments and the accompanying drawings, inwhich

FIG. 1 shows a simplified example of a telecommunication system,

FIG. 2 is a flow chart,

FIG. 3 illustrates one example of a bit rate allocation method,

FIG. 4 illustrates another example of the bit rate allocation method,

FIG. 5 illustrates another example of the bit rate allocation method,

FIG. 6 shows an example of a Radio Network Controller,

FIG. 7 shows an example of a Base Station.

DESCRIPTION OF EMBODIMENTS

With reference to FIG. 1, examine an example of a data transmissionsystem in which the preferred embodiments of the invention can beapplied. The invention can be implemented in the RNC (Radio NetworkController) and/or BS (Base Station) and can e.g. be a part of RAN(Radio Access Network) for instance UTRAN (UMTS Terrestrial Radio AccessNetwork) solution as well as IPRAN (Internet Protocol RAN).

In FIG. 1 the embodiments are described in a simplified radio systemrepresenting a Code Division Multiple Access, CDMA, system. CodeDivision Multiple Access is used nowadays for example in radio systemsknown at least by the names IMT-2000 (International MobileTelecommunications 2000) and UMTS (Universal Mobile TelecommunicationsSystem). The embodiments are not, however, restricted to these systemsgiven as examples but a person skilled in the art may apply the solutionin other radio systems provided with the necessary properties.

FIG. 1 is a simplified block diagram describing the most importantnetwork elements of the radio system and the interfaces between them.The structure and function of the network elements are not described indetail because they are generally known.

The main parts of the radio system are a core network (CN) 100, a radioaccess network 130 and user equipment (UE) 170. The term UTRAN is anabbreviation from UMTS Terrestrial Radio Access Network, i.e. the radioaccess network belongs to the third generation and is implemented bywideband code division multiple access WCDMA. Generally, the radiosystem can also be defined as follows: the radio system consists of auser terminal, which is also called a subscriber terminal or a mobilestation, and of a network part, which includes the fixed infrastructureof the radio system, i.e. a core network, a radio access network and abase station system.

A mobile services switching centre (MSC) 102 is the centre of thecircuit-switched side of the core network 100. The mobile servicesswitching centre 102 is used to serve the connections of the radioaccess network 130. The tasks of the mobile services switching centre102 typically include switching, paging, user terminal locationregistration, handover management, collection of subscriber billinginformation, data encryption parameter management, frequency allocationmanagement and echo cancellation.

The number of mobile services switching centres 102 may vary: a smallnetwork operator may have only one mobile services switching centre 102,whereas large core networks 100 may have several ones. FIG. 1 showsanother mobile services switching centre 106 but for the sake of clarityits connections to other network elements are not illustrated.

Large core networks 100 may comprise a separate gateway mobile servicesswitching centre (GMSC) 110, which is responsible for circuit-switchedconnections between the core network 100 and the external networks 180.The gateway mobile services switching centre 110 is located between themobile services switching centres 102, 106 and the external networks180. The external network 180 may be, for example, a public land mobilenetwork PLMN or a public switched telephone network PSTN.

The core network 100 typically comprises other parts, too, such as ahome location register HLR, which includes a permanent subscriberregister and, if the radio system supports the GPRS, a PDP address(PDP=Packet Data Protocol), and a visitor location register VLR, whichincludes information on roaming of the user terminals 170 in the area ofthe mobile services switching centre 102. For the sake of clarity, allthe parts of the core network are not shown in FIG. 1.

A serving GPRS support node (SGSN) 118 is the centre of thepacket-switched side of the core network 100. The main task of theserving GPRS support node 118 is to transmit and receive packets withthe user terminal 170 supporting packet-switched transmission, utilizingthe radio access network 130. The serving GPRS support node 118 includesuser information and location information on the user terminal 170.

A gateway GPRS support node (GGSN) 120 on the packet-switched sidecorresponds to the gateway mobile services switching centre 110 of thecircuit-switched side, with the exception that the gateway GPRS supportnode 120 has to be able to route outgoing traffic from the core network100 to external networks 182, whereas the gateway mobile servicesswitching centre 110 typically routes only incoming traffic. In theexample, the external networks 182 are represented by the Internet, viawhich a considerable part of wireless telephone traffic can betransmitted in the future.

The radio access network 130 consists of radio network subsystems 140,150. Each radio network subsystem 140, 150 consists of radio networkcontrollers (RNC) 146, 156 and B nodes 142, 144, 152, 154. The B node israther an abstract concept and therefore frequently replaced by the term‘base station’.

The radio network controller 146, 156 is usually responsible for thefollowing tasks, for example: management of the radio resources of thebase transceiver station or B-node 142, 144, 152, 154, intercellhandover, measurement of time delays on the uplink, implementation ofthe operation and management interface, and management of power control.

The radio network controller 146, 156 includes at least one transceiver.One radio network controller 146, 156 may serve one cell or severalsectorized cells. The cell diameter may vary from a few metres to dozensof kilometres. The radio network controller 146, 156 is often deemed toinclude a transcoder, too, for performing conversion between the speechcoding format used in the radio system and the speech coding format usedin the public switched telephone system. In practice the transcoder,however, is usually located in the mobile services switching centre 102.The radio network controller 146, 156 is usually responsible for thefollowing tasks, for example: measurements on the uplink, channelcoding, encryption and scrambling coding.

The user terminal 170 consists of two parts: mobile equipment (ME) 172and a UMTS subscriber identity module (USIM) 174. The user terminal 170comprises at least one transceiver for establishing a radio connectionto the radio access network 130. The user terminal 170 may include atleast two different subscriber identity modules. In addition, the userterminal 170 comprises an antenna, a user interface and a battery.Nowadays various kinds of user terminals 170 are available, e.g.terminals that are installed in a car and portable terminals. The userterminals 170 also have properties similar to those of a personalcomputer or a portable computer.

The USIM 174 includes information on the user and on data security, e.g.an encryption algorithm, in particular.

It is obvious to a person skilled in the art that the interfacesincluded in the radio telecommunications system are determined by thehardware implementation and the standard used, for which reason theinterfaces of the system may differ from those shown in FIG. 1. In theUMTS, the most important interfaces are the Iu interface between thecore network and the radio access network, which is divided into theIuCS (CS=Circuit Switched) interface of the circuit-switched side andthe IuPS (PS=Packet Switched) interface of the packet-switched side, andthe Uu interface between the radio access network and the user terminal.The interface defines what kind of messages different network elementsmay use to communicate with one another. The object of thestandardisation of interfaces is to enable function between networkelements of different producers. In practice, however, some of theinterfaces are producer-specific.

The FIG. 2 shows a flow chart of a preferred embodiment of the bit rateallocation method that uses the QoS classification according to theinvention. The embodiment is based on some QoS parameters such asAllocation Retention Priority (ARP), Traffic Class (TC) or TrafficHandling Priority (THP), but it is possible to use other suitableparameters as well. The method is especially suitable for packettransfer.

In the following, some parameters that can be used in the method areexplained briefly.

Traffic Class, TC, parameter means typically the same as the UMTS QoS(Quality of Service) classes. There are four different QoS, or TC,classes: conversational class, streaming class, interactive class andbackground class. The main distinguishing factor between these classesis how delay sensitive the traffic is. For instance, conversationalclass is meant for traffic which is remarkably delay sensitive, whilebackground class is meant for traffic which tolerates even relativelylong delays.

Traffic Handling Priority, THP is a UMTS parameter which specifies therelative importance of handling all SDUs belonging to the UMTS bearercompared to the SDUs of other bearers. SDU, i.e. Service Data Unit, inother words an information unit passed from one protocol layer toanother. The Traffic Handling Priority parameter is used fordifferentiating between bearer qualities. This parameter is availableonly for the interactive traffic class.

The Allocation Retention Priority, ARP, parameter is used fordifferentiating between bearers when performing allocation and retentionof a bearer. In situations where resources are scarce, the relevantnetwork elements can use the Allocation/Retention Priority to prioritizebearers with a high Allocation/Retention Priority over bearers with alow Allocation/Retention Priority when performing admission control.

The end-to-end QoS in UMTS is supported by several bearer services:first level service, local bearer service, UMTS bearer service andexternal bearer service. The UMTS bearer service consists of RAB (RadioAccess Bearer) service and the core network bearer service. The airinterface, the UTRAN and the Iu interface belong to the RAB service.UMTS specifications define four QoS classes corresponding to varioustraffic requirements, typically delay tolerance. The QoS classes are:conversational class for phone calls, streaming class for on-line audioand video connections, interactive class for web browsing, etc. andbackground class for different data applications such as packet-data.

More details about QoS can be found in the literature and standards ofthe field.

The method begins in block 200. In block 202 the number of bit rateclasses are determined. The number of the classes depends on the currentneed and system. The bit rates, and thus the amount of bit rate classes,are usually determined by the specifications and/or circumstances, suchas available capacity.

In block 204 the bit rates for the bit rate classes are set. The bitrates are usually set by the operator within the limits of the availablecapacity. They can thus be changed according to the current system. Inthis application, these bit rates are called minimum bit rates in thisapplication. The minimum bit rate is set to be class-specific orgeneral, i.e. the same for all classes. It is also possible to set botha common or general minimum bit rate for all classes, and in addition,class-specific minimum bit rates. There are other possibilities, too.Attention has to be paid to the fact that bit rates tend to growaccording to technical development. Nowadays typical bit rates are 32kbps, 64 kbps and 128 kbps. If these bit rates are used, the generalminimum bit rate can be for instance 32 kbps. The users are divided intoclasses typically according to the price they pay for a connection.

The maximum transmission power target is set in block 206. In CDMAsystems, such as UMTS, power control is a key issue, because many usersemploy the same frequency and thus cause interference to each other.This is why a maximum transmission power target is set. On the otherhand, in cellular systems transmission power defines the size of thecell. In addition, power control is important in the CDMA-networksbecause of the near-far problem. The target is system-dependent and itis determined by the operator.

In block 208 the resource requests are arranged into a queue. The userscan be arranged in many different ways. For example, the user who firstasked for radio resources is the first in the queue. The principlesaccording to which the users are put in order vary according to thecurrent needs.

The resources are allocated on the basis of the requests in the queue inblock 210. Typically, the resources are allocated according to the queueorder. In other words, the first to get resources is the first in thequeue. The Allocation process can of course be arranged in other ways,too. Allocation continues until the maximum power target is achieved.

Arrow 222 depicts one possible embodiment of the invention in which bitrates are only allocated, not increased or decreased. The load controlhas to be implemented in some other way.

In another preferred embodiment of the invention it is possible tochange, to increase or decrease, bit rates. In block 212 it is checked,whether the maximum power target is achieved or not. If it is notachieved, the bit rates are increased in block 214 on the basis of thequeue until the maximum power target is achieved. Typically, the bitrate of the user who is first in the queue is raised first, the bit rateof the second user, is raised next, etc.

In block 216 it is checked, whether the resource requests cause too muchload in relation to the maximum power target. If the load is too high,the bit rates are decreased in block 218. The reduction is made, forinstance, according to the following rules: bit rates higher than theminimum bit rate of their class or higher than the common minimum bitrate are decreased first and users whose a bit rate is equal to theminimum are transferred to the control channel (CCH). Control Channel isa logical radio channel that carries system management messages betweena base transceiver station and a mobile station. A mobile communicationnetwork may have several control channels, for example a broadcastcontrol channel (BCCH), common control channel (CCCH) and associatedcontrol channel (ACCH). In this method, the typically used channels areRACH (Random Access Channel) and FACH (Forward Access Channel).

The decreasing continues until the common load is below the transmissionpower target.

The method ends in block 220. Arrow 224 shows one possible way ofrepeating the method.

Next, the preferred embodiments are explained in further detail by meansof examples. In the following examples, the user class is based on theQoS parameter called ARP, Allocation Retention Priority. There are threebit rate classes, called gold, silver and bronze, of which the goldclass has the highest and the bronze the lowest minimum bit rate. Theexamples relate to packet transmission. The concept of the minimum bitrate refers to the maximum bit rate in a TFCS set. The TFCS set is a setof transport format combinations to be used by the mobile station, whichallows bit rates to be chosen on a TTI basis. TTI, Transmission TimeInterval, is equal to the frame length. In the examples, a generalminimum bit rate value of 32 kbps and several class-specific minimum bitrates have been set: for gold class 128 kbps, for silver class 64 kbpsand for bronze class 32 kbps.

For the sake of simplicity, the examples, do not take into account thatusually different users, even if they use the same kbit rate, needdifferent amounts of power due to different radio conditions.

FIG. 3 illustrates one example of the bit rate allocation method. Thetransmission power target is shown by dotted line 300. The resourcerequests are in the queue as follows: users number 2, 4 and 5 are goldusers, users number 1 and 6 are silver users and users number 3 and 7are bronze users.

In the first step, the first user in the queue is allocated his minimumbit rate 64 kbps 302. Then, in step 2, the second user is allocated hisminimum bit rate 128 kbps 304. The process continues until the usersnumber 3, 4 and 5 are allocated their bit rates, marked in FIG. 3 withnumbers 306, 308 and 310. The user 3 has a bit rate of 32 kbps and theusers 4 and 5 have bit rates of 128 kbps. Then it is noticed that thesystem cannot accept the next user, number 6, marked in FIG. 3 withnumber 312, because he needs too much capacity, 64 kbps. Then the useris offered as high a bit rate as possible, in this case 32 kbps, markedin FIG. 3 with number 314. 32 kbps is in this example the generalminimum bit rate. There is still another user in the queue, user number7, but there is not enough space for him either in the system, thereforean attempt is made to allocate him the general minimum bit rate of 32kbps. This is shown in FIG. 3 with number 316. This time, there is nospace with that bit rate either, so this user has to wait for space tobecome available or he is transferred to a control channel.

FIG. 4 illustrates another example of the bit rate allocation method.This example shows how bit rates can be increased if the transmissionpower target 400 is not yet achieved and all the users in the queue arealready allocated their resources. In the queue, there are three users:the first one is a silver user, the second is a gold user and the thirdis a bronze user.

In the beginning, the first user is allocated the minimum bit rate ofhis class, 64 kbps 402. Then the second user is allocated the minimumbit rate of his class, 128 kbps 404. The allocation process continuesuntil all the users in the queue are allocated their resources. In thisexample, the last user is the third user, who is allocated the minimumbit rate of his class 32 kbps 406.

After this, the bit rate increase starts in step 4. The bit rate isincreased in this example in the order of the queue. In other words, thefirst user is the first one to get the higher bit rate of 128 kbpsmarked in FIG. 4 with number 408. Next one is the second user, who getsthe new bit rate of 256 kbps number 410.

The transmission power target is not yet achieved, so the increaseprocess continues in step 6. The third user is given the higher bit rateof 64 kbps marked in FIG. 4 with number 412. The process continues inthe next step where the first user gets the higher bit rate again. Thenew bit rate is 256 kbps marked with number 414. Then it is noticed thatthe target is exceeded, so the algorithm transfers a part of the bitrate of the first user to the second user, whereby the second user getshigher bit rate of 384 kbps 418 and the bit rate of the first user is128 kbps 416. The target still remains exceeded and therefore in step 9the algorithm transfers a part of the bit rate of the second user to thethird user. The third user gets a new bit rate of 128 kbps marked withnumber 420, and the bit rate of the second user is 256 kbps marked withnumber 410. Now the whole capacity is used and all the users in thequeue have been allocated their bit rates.

FIG. 5 depicts another example of the bit rate allocation method. Thisexample shows, how bit rates can be decreased if the transmission powertarget 500 is exceeded. In the beginning there are 5 users who has beenallocated the minimum bit rate of their classes or higher bit rates. Thefirst user has a bit rate of 128 kbps number 502, the second also has128 kbps 504, the third 32 kbps 506, the fourth 64 kbps 508 and thefifth 32 kbps 510. The general minimum bit rate used is 32 kbps. This isthe absolute minimum, below which the rate cannot go.

The first user is a silver user and therefore has a minimum bit rate of64 kbps. Thus the first one to get a lower bit rate is the first user.His new bit rate is 64 kbps, which is the minimum bit rate of his class.This is marked in FIG. 5 with number 512. There is still too much loadand therefore the decreasing process has to continue. In step 2, thefourth user, who is a silver user and has the minimum bit rate of hisclass, gets a lower bit rate of 32 kbps number 514.

In the next step, step 3, there are two options: the first user again,who now has the minimum bit rate of his class or the second user, whohas the minimum bit rate of his class. This time the gold user, usernumber 2 is chosen and he is allocated a lower bit rate of 64 kbpsmarked in FIG. 5 with number 516. Next user 1 is given a lower bit rateof 32 kbps 518. Then user 2 is given a new lower bit rate, which is also32 kbps. Also the user 2 is given a new lower bit rate of 32 kbps markedwith the number 520. Now, in step 5 the algorithm notices that all theusers have the same bit rate, the general minimum and thus the bit ratecannot be reduced anymore. There is still too much load and thereforeone user has to be removed to another channel, typically to a controlchannel (CCH). A mobile communication network may have several controlchannels, for example a broadcast control channel (BCCH), common controlchannel (CCCH) and associated control channel (ACCH). In this method,the typically used channels are RACH (Random Access Channel) and FACH(Forward Access Channel).

After this, the load is below the transmission power target and theallocation process is completed.

It is obvious that the increasing and decreasing processes can also becombined.

There is also a radio link aspect in the bit rate allocation describedabove, since each link has its maximum power that determines the bordersof the cell. The transmission power is thus set in the radio networkplanning process. The radio coverage depends on the maximum of theallocated power per link for a certain load factor. If the maximum poweron every link is equal for all the bit rates, then the coverage area forlow bit rates is larger than for high bit rates. There are two optionsfor taking this into consideration in the bit rate allocation: either togive the maximum power per link to the different user classes in such away that the coverage area or cell size is the same for all or to acceptthe different sizes of the coverage areas for the different bit ratesand give gold users a lower bit rate at the cell border. Cell coverageis a problem mainly in large cells.

FIG. 6 shows a simplified functional example of a radio networkcontroller (RNC) where the embodiments of the data transmission methodcan be accomplished. For a person skilled in the art it is clear thatthe radio network controller can differ from what is depicted in FIG. 6.

RNC is, as mentioned above, the switching and controlling element ofUTRAN. UTRAN is the network element of the UMTS network. The switcingunit 600 takes care of the connection between the core network and theuser equipment. The radio network controller is located between the Iub602 and Iu 614 interfaces. There is also an interface Iur for inter-RNCtransmission 616. The blocks 604 and 612 depict interface units betweenthe radio network controller and other network. The preciseimplementation of the radio network controller is producer-dependent.

The functionality of the radio network controller can be classified intotwo classes: UTRAN radio resource management 608 and control functions606. An operation and management interface function 610 serves as amedium for information transfer to and from network managementfunctions. The radio resource management is a group of algorithms usedto share and manage the radio path connection so that the quality andcapacity of the connection are adequate. The most important radioresource management algorithms are handover control, power control,admission control, packet scheduling, and code management. The UTRANcontrol functions take care of functions related to the set-up,maintenance and release of a radio connection between base stations anduser equipment.

The radio network controller performs the actions needed in the bit rateallocation method described above such as forming the user queue andincreasing or decreasing the bit rates. This process also requires amemory unit 618 where for example the information on minimum bit ratesis stored.

The disclosed functionalities of the described embodiments of the datatransmission method can be advantageously implemented by means ofsoftware that typically locates in the radio resource management block608 of the radio network controller. The implementation solution canalso be for instance an ASIC (Application Specific Integrated Circuit)component.

FIG. 7 shows a simplified example of a transmitter of a base station, ora node B, where the embodiments of the data transmission method can alsobe implemented. For a person skilled in the art it is clear that thetransceiver can differ from what is depicted in FIG. 7. In this example,the network offers the base station the following information: thenumber of bit rate classes, bit rates of the bit rate classes and themaximum transmission power target.

Block 700 is a DSP, Digital Signal Processor, which for example codes,ciphers and interleaves data before transmitting it. The bit rateallocation according to the embodiment of the invention can be carriedout in the DSP block, for instance as a part of packet scheduling,especially in the HSDPA (High Speed Packet Access).

Block 702 is a modulator modulating a carrier with data. There are manydifferent modulation methods and the current radio system determineswhich one will be used. Basically, the modulation methods are dividedinto three classes: amplitude modulation, frequency modulation and phasemodulation. The names denote the signal characteristic that changes andthus carries the information. Naturally, the modulation methods can alsobe combined. More about modulation and different modulation methods canbe read in the literature of the art.

Block 704 is a spreader which in wideband systems spread the signalspectrum on a wider band. The spreading is typically performed bymultiplying a modulated narrowband signal by a pseudo-random code. It isobvious that if the system is a narrowband system, this block is notincluded in the transmitter. The spread spectrum systems are widelyknown in the field, and therefore they are not explained here in furtherdetail.

Block 706 is a digital-to-analog converter which transforms the signalto an analog form. The converters are also known by a person skilled inthe art.

Block 708 is a radio frequency block which usually comprises anupconverter that converts a base band signal to the intermediatefrequency or straight to the radio frequency. The radio frequency blockusually also comprises a power amplifier for amplifying the signal tothe needed transmitting power. The signal is then taken to an antenna,not shown in FIG. 7.

The disclosed functionalities of the described embodiments of the datatransmission method can be advantageously implemented by means ofsoftware that typically locates in the digital signal processor 700. Theimplementation solution can also be for instance an ASIC (ApplicationSpecific Integrated Circuit) component.

Even though the invention is described above with reference to anexample according to the accompanying drawings, it is clear that theinvention is not restricted thereto but it can be modified in severalways within the scope of the appended claims.

1. A data transmission method in a telecommunication system, the methodcomprising: determining the number of bit rate classes; setting bitrates for the bit rate classes; setting a maximum transmission powertarget; arranging resource requests into a queue; allocating resourcesaccording to the requests in the queue until the maximum power target isachieved.
 2. A data transmission method in a telecommunication system,the method comprising: determining the number of bit rate classes;setting bit rates for the bit rate classes; setting a maximumtransmission power target; arranging resource requests into a queue;allocating resources according to the requests in the queue; if themaximum power target is not achieved when resources have been allocatedto all the users in the queue, increasing the bit rates on the basis ofthe queue until the maximum power target is achieved; if the resourcerequests cause too much load in relation to the maximum power target,decreasing the required number of bit rates in a predetermined way. 3.The method of claim 1, further comprising determining the bit rateclasses on the basis of the required Quality of Service, QoS.
 4. Themethod of claim 1, further comprising setting the bit rate classes onthe basis of a Quality of Service, QoS, parameter ARP, AllocationRetention Priority.
 5. The method of claim 2, further comprising: whenthe maximum power threshold is exceeded the bit rate decreasing byallocating to the user a general minimum bit rate.
 6. The method ofclaim 2, further comprising: when the maximum power threshold isexceeded the bit rate decreasing by allocating to the user aclass-specific minimum bit rate.
 7. The method of claim 2, wherein thedecreasing of the bit rate starts form the user who has a bit ratehigher than the general minimum bit rate and the lowest priority,followed by the user who has a bit rate higher than the class specificminimum bit rate and the lowest priority.
 8. The method of claim 2,further comprising: if a general minimum bit rate or a class specificminimum bit rate is allocated to the users and the load remains toohigh, the required number of users are transferred to the controlchannel.
 9. A radio network controller comprising: means for determiningthe number of bit rate classes; means for setting bit rates for the bitrate classes; means for setting a maximum transmission power target;means for arranging resource requests into a queue; means for allocatingresources according to the requests in the queue until the maximum powertarget is achieved.
 10. A radio network controller comprising: means fordetermining the number of bit rate classes; means for setting bit ratesfor the bit rate classes; means for setting a maximum transmission powertarget; means for arranging resource requests into a queue; means forallocating resources according to the requests in the queue; means forincreasing the bit rates on the basis of the queue until the maximumpower target is achieved; means for decreasing the required number ofbit rates in a predetermined way.
 11. The radio network controller ofclaim 10, further comprising means for determining the bit rate classeson the basis of the required Quality of Service, QoS.
 12. The radionetwork controller of claim 10, further comprising means for setting thebit rate classes on the basis of a Quality of Service, QoS, parameterARP, Allocation Retention Priority.
 13. The radio network controller ofclaim 10, further comprising means for decreasing the bit rate byallocating a general minimum bit rate to a user.
 14. The radio networkcontroller of claim 10, further comprising means for decreasing the bitrate by allocating the class specific minimum bit rate to a user. 15.The radio network controller of claim 10, further comprising means forstarting the decreasing of the bit rate from the user who has a bit ratehigher than the general minimum bit rate and the lowest priority,followed by the user who has a bit rate higher than the class specificminimum bit rate and the lowest priority.
 16. The radio networkcontroller of claim 10, further comprising means for transferring theneeded number of users onto the control channel.
 17. A base stationcomprising: means for arranging resource requests into a queue; meansfor allocating resources according to the requests in the queue.
 18. Abase station comprising: means for arranging resource requests into aqueue; means for allocating resources according to the requests in thequeue; means for increasing the bit rates on the basis of the queueuntil the maximum target set for the transmission power is achieved;means for decreasing the required number of bit rates in a predeterminedway.
 19. A radio network controller configured to: determine the numberof bit rate classes; set bit rates for the bit rate classes; set amaximum transmission power target; arrange resource requests into aqueue; allocate resources according to the requests in the queue untilthe maximum power target is achieved.
 20. A radio network controllerconfigured to: determine the number of bit rate classes; set bit ratesfor the bit rate classes; set a maximum transmission power target;arrange resource requests into a queue; allocate resources according tothe requests in the queue; increase the bit rates on the basis of thequeue until the maximum power target is achieved; decrease the requirednumber of bit rates in a predetermined way.
 21. A base stationconfigured to: arrange resource requests into a queue; allocateresources according to the requests in the queue.
 22. A base stationconfigured to: arrange resource requests into a queue; allocateresources according to the requests in the queue; increase the bit rateson the basis of the queue until the maximum target set for thetransmission power is achieved; decrease the required number of bitrates in a predetermined way.